Bi-directional tractor exhaust system with ground speed detection

ABSTRACT

A bi-directional tractor exhaust system with ground speed detection includes a downwardly directed exhaust pipe, an upwardly directed exhaust pipe, and an intermediate exhaust pipe connected to the outlet of a diesel particulate filter. An exhaust pipe valve may be opened or closed by an actuator to direct exhaust through the downwardly directed exhaust pipe during regeneration of the diesel particulate filter if a signal from a ground speed sensor indicates ground speed above a first speed, or through the upwardly directed exhaust pipe if the ground speed is below a second speed.

FIELD OF THE INVENTION

This invention relates generally to tractor exhaust systems, andspecifically to exhaust systems for use on small and/or compact tractorshaving elevated exhaust temperatures during regeneration of a dieselparticulate filter.

BACKGROUND OF THE INVENTION

Small and/or compact tractors with internal combustion engines havecommonly used downwardly directed exhaust pipes for many applications.Downwardly directed exhaust pipes direct exhaust below the internalcombustion engine and are preferred for small and/or compact tractorapplications such as mowing, road transport, general field work and workinside buildings. Upwardly directed exhaust pipes direct exhaust upabove the engine and are more suited for other applications such asloader work, snow blowing, working in vegetable fields or on sensitiveturf grass, working near livestock, or stationary applications includingrunning an aeration pump or grain auger.

Recently, efforts to reduce emissions including Tier 4 regulations haveresulted in small and/or compact tractors having elevated exhausttemperatures at certain times. Specifically, emissions reduction devicessuch as diesel particulate filters (DPFs) periodically result inelevated exhaust temperatures such as approximately 600 degrees C.during regeneration. Other emissions reduction devices or exhausttreatment devices also may result in high exhaust temperatures. However,it is preferred that a small and/or compact tractor's downwardlydirected exhaust temperatures should not exceed approximately 200degrees C., which may be the maximum normal operating temperature of theexhaust.

Attempts to reduce high exhaust temperature down to the normal maximumexhaust temperature of 200 degrees C. have not been successfullyimplemented in small and/or compact tractors. For example, aspiratorsand venturis have not been effective because space constraints preventsizing aspirators and venturis large enough to achieve the 200 degree C.outlet temperature needed for downward exhaust.

A small and/or compact tractor exhaust system is needed to preventdownwardly directed exhaust exceeding 200 degrees C. A system is neededthat limits or reduces high temperature downwardly directed exhaustwithout aspirators or venturis. A system is needed that allows exhaustto exit through downwardly directed exhaust pipes for some applications,and through upwardly directed exhaust pipes for other applications. Asystem is needed that directs exhaust during high temperature engineregeneration downwardly when safe to do so, and to reduce or minimizeoperator discomfort.

SUMMARY OF THE INVENTION

A bi-directional tractor exhaust system with ground speed detectionincludes a downwardly directed exhaust pipe connected to an upwardlydirected exhaust pipe, and an exhaust pipe valve mounted in thedownwardly directed exhaust pipe. An actuator connected to the exhaustpipe valve is moveable between a first position opening the exhaust pipevalve to direct exhaust through the downwardly directed exhaust pipe,and a second position closing the exhaust pipe valve to direct exhaustthrough the upwardly directed exhaust pipe. A microcontroller connectedto the actuator and to a ground speed detector signals the actuator tomove the exhaust pipe valve to the first position above a first groundspeed, or to the second position below a second ground speed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a small and/or compact tractor with abi-directional tractor exhaust system according to one embodiment of theinvention.

FIG. 2 is a perspective view of a bi-directional tractor exhaust systemaccording to one embodiment of the invention

FIG. 3 is a perspective view, partially in section, of a bi-directionaltractor exhaust system according to the embodiment of FIG. 2.

FIG. 4 is a perspective view of a bi-directional tractor exhaust systemaccording to a second embodiment of the invention.

FIG. 5 is a perspective view, partially in section, of a bi-directionaltractor exhaust system according to the embodiment of FIG. 4.

FIG. 6 is a perspective view of a bi-directional tractor exhaust systemaccording to a third embodiment of the invention.

FIG. 7 is a logic diagram of a bi-directional tractor exhaust systemwith ground speed detection according to an alternative embodiment ofthe invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

In an embodiment of the invention shown in FIG. 1, small and/or compacttractor 100 may be provided with bi-directional tractor exhaust system102. The bi-directional tractor exhaust system may include one or morevalves to direct exhaust from internal combustion engine 101 eitherbelow the engine through downwardly directed exhaust pipe 104, orvertically above the engine through upwardly directed exhaust pipe 116.The internal combustion engine may be a diesel engine with a dieselparticulate filter 114, or alternatively may be a gas engine.Intermediate exhaust pipe 106 may be positioned between the downwardlydirected exhaust pipe and upwardly directed exhaust pipe at or adjacentthe outlet of diesel particulate filter 114. Alternatively, thedownwardly directed exhaust pipe and upwardly directed exhaust pipe maybe joined together at the outlet of any other emissions reduction orexhaust treatment device having high exhaust temperatures at certaintimes of operation.

In an embodiment of the invention shown in FIGS. 2-3, the bi-directionaltractor exhaust system may include exhaust pipe valve 108 in downwardlydirected exhaust pipe 104. In FIG. 3, exhaust pipe valve 108 is shown ina first or open position so that exhaust exits through the downwardlydirected exhaust pipe. Exhaust pipe valve 108 may be a butterfly valvethat an operator may open and close using actuator 109. Exhaust pipevalve 108 also may be moved to a second or closed position, so thatexhaust exits upwardly through upward exhaust pipe 116. The actuator mayinclude tab 110 that may contact on-off switch 111 when the actuatorcloses exhaust pipe valve 108. Switch 111 may be connected to controller112. The controller may include logic preventing regeneration of dieselparticulate filter 114 unless exhaust pipe valve 108 is in the secondclosed as indicated by the position of switch 111.

In the embodiment of FIGS. 2-3, upwardly directed exhaust pipe 116 maybe located within intermediate exhaust pipe 106. The upwardly directedexhaust pipe may have a smaller diameter than the intermediate exhaustpipe and may extend below outlet 117 of diesel particulate filter 114.Cap 118 may be pivotably mounted to the top of upward exhaust pipe 116.The cap's weight may urge the cap to the closed position when exhaustpipe valve 108 is open and exhaust exits downwardly. The cap may pivotto an open position when exhaust pipe valve 108 is closed and there isincreased pressure in upward exhaust pipe 116.

In the embodiment of FIGS. 4-5, bi-directional tractor exhaust system202 may include first and second exhaust valves 212, 213 positioned inintermediate exhaust pipe 207 between downwardly and upwardly directedexhaust pipes 204, 206. Outlet 215 of diesel particulate filter 214 maybe connected to the intermediate exhaust pipe between first valve 212and second valve 213.

In FIG. 5, exhaust pipe valve 212 is shown in the open position andexhaust pipe valve 213 is closed so that exhaust may exit through thedownwardly directed exhaust pipe. Exhaust pipe valves 212, 213 may bebutterfly valves that may be opened and closed using exhaust temperaturecontrols 203. When exhaust pipe valve 212 is closed and exhaust pipevalve 213 is open, exhaust may exit through upward exhaust pipe 206.Mechanical linkage 223 may be provided between valves 212 and 213 tosimultaneously open one valve while closing the other valve, so thatonly one valve is open at the same time.

In the embodiment of FIGS. 4-5, exhaust temperature valve controls 203may include a temperature sensor such as thermistor 205 connected to arelay that powers solenoid 211 to open or close valves 212 and 213. Whenexhaust temperature is in a normal range, typically below a specifiedtemperature such as 200 degrees C., the voltage drop across thermistor205 may be small. The thermistor's small voltage drop may engage a relaywhich provides power to solenoid 211 to open first valve 212 and closesecond valve 213 to direct exhaust downwardly through exhaust pipe 204.When exhaust temperature periodically increases above the normal rangeor specified temperature such as 200 degrees C., the voltage drop acrossthermistor 205 may be larger. The voltage may be high enough todisengage solenoid 211 and cause first valve 212 to close while secondvalve 213 opens, directing exhaust upwardly through pipe 206.

In the embodiment of FIG. 6, bi-directional tractor exhaust systemcontrols may include microcontroller 220 and operator switch 222connected to CAN network 224. Microcontroller 220 may monitor exhausttemperature via a temperature sensor in or connected to dieselparticulate filter 214. When the microcontroller receives signals fromthe temperature sensor indicating regeneration of the diesel particulatefilter, or indicating exhaust temperature above the normal range ormaximum such as 200 degrees C., the microcontroller may cut off power tosolenoid 211 causing first valve 212 to close and second valve 213 toopen. The microcontroller also may include logic to prevent enteringregeneration unless first valve 212 is closed and second valve 213 isopen, thus preventing exhaust from exiting downwardly duringregeneration.

In the embodiment of FIG. 6, the bi-directional exhaust system also mayinclude operator switch 222 that an operator may actuate from thetractor cab to open or close valves 212, 213 to direct exhaust eitherdownwardly or upwardly. The operator switch may function independentlyof the exhaust temperature valve controls, or the exhaust temperaturecontrols may override the operator switch. For example, if thetemperature sensor indicates regeneration or indicates exhausttemperature exceeds a maximum such as 200 degrees C., microcontroller220 may override operator switch 222 and cut off power to solenoid 211,close first valve 212 and open second valve 213 so that exhaust exitsupwardly. Additionally, first valve 212 may return to the closedposition and second valve 213 may open if power is lost or removed fromthe system.

In an alternative embodiment, the bi-directional exhaust system withground speed detection may include vehicle ground speed sensor 300connected to microcontroller 112. The microcontroller may receivesignals from the vehicle ground speed sensor and may operate one or moreexhaust system valves based on the input from the ground speed sensorand the status of exhaust regeneration or, alternatively, the exhausttemperature. The microcontroller may command or allow the exhaust systemvalve to the downwardly directed or upwardly directed exhaust positionby providing electrical signals to a solenoid, stepper motor, servo orother electromechanical device. The vehicle ground speed sensor may be aHall effect sensor mounted to the tractor frame as shown in FIG. 1, or asimilar ground speed sensor.

FIG. 7 provides an example of software or logic that a vehiclecontroller or microcontroller 112 may use in a bi-directional exhaustsystem with vehicle ground speed detection. In block 301,microcontroller 112 may check the status of exhaust regeneration. Forexample, the microcontroller may monitor one or more sensors thatmeasure back pressure and/or temperature, including sensors used to makedecisions on when to activate and/or deactivate the regeneration cycle.If the regeneration cycle is not active or required, the microcontrollermay command or allow the exhaust valve to remain in the downwardlydirected exhaust position in block 302, which may be the defaultposition for each valve in the bidirectional exhaust system. Themicrocontroller then may continue to monitor regeneration status inblock 301. If the regeneration cycle is active or required, in block 303the microcontroller may check vehicle ground speed based on data inputfrom the vehicle ground speed sensor.

In the embodiment of FIG. 7, if the microcontroller determines, based oninput from the vehicle ground speed sensor, that the vehicle is moving(for example, at least 3.0 kph) for at least a specified time (forexample, 5 seconds), in block 304 the microcontroller may command orallow the exhaust valve to stay in the downwardly directed exhaustposition. If the microcontroller determines, based on input from thevehicle ground speed sensor, that the vehicle is stationary (forexample, less than 0.5 kph) for at least a specified time (for example,10 seconds), in block 306 the microcontroller may command or allow theexhaust valve to the upwardly directed exhaust position. If themicrocontroller determines, based on input from the vehicle ground speedsensor, that the vehicle does not meet the moving or stationary speed ortime requirements in blocks 304 or 306, in block 305 the microcontrollermay not move or change the position of the exhaust valve. Themicrocontroller then may continue to monitor regeneration status inblock 301.

Having described a preferred embodiment, it will become apparent thatvarious modifications can be made without departing from the scope ofthe invention as defined in the accompanying claims.
 1. A bi-directionaltractor exhaust system, comprising: a downwardly directed exhaust pipeconnected to an upwardly directed exhaust pipe; an exhaust pipe valvemounted in the downwardly directed exhaust pipe; an actuator connectedto the exhaust pipe valve and moveable between a first position openingthe exhaust pipe valve to direct exhaust through the downwardly directedexhaust pipe, and a second position closing the exhaust pipe valve todirect exhaust through the upwardly directed exhaust pipe; and amicrocontroller connected to the actuator and to a ground speeddetector, the microcontroller signaling the actuator to move the exhaustpipe valve to the first position above a first ground speed, or to thesecond position below a second ground speed.
 2. The bi-directionaltractor exhaust system of claim 1 wherein the downwardly directedexhaust pipe and upwardly directed exhaust pipe are connected togetheradjacent an outlet of a diesel particulate filter.
 3. The bi-directionaltractor exhaust system of claim 2 wherein the controller moves theexhaust pipe valve to the second position only during regeneration ofthe diesel particulate filter.
 4. The bi-directional tractor exhaustsystem of claim 2 further comprising an intermediate exhaust pipepositioned between the downwardly directed exhaust pipe and the upwardlydirected exhaust pipe, the upwardly directed exhaust pipe positionedinside and having a smaller diameter than the intermediate exhaust pipe.5. The bi-directional tractor exhaust system of claim 1 wherein theexhaust pipe valve is a butterfly valve.
 6. A bi-directional tractorexhaust system, comprising: an exhaust valve directing exhaust through adownwardly directed exhaust pipe or through an upwardly directed exhaustpipe connected together adjacent a diesel particulate filter; and amicrocontroller connected to the diesel particulate filter, the exhaustvalve and a ground speed sensor, the microcontroller commanding thevalve to direct exhaust through the downwardly directed exhaust pipeduring regeneration of the diesel particulate filter unless the groundspeed sensor indicates a first speed for at least a first time.
 7. Thebi-directional tractor exhaust system of claim 6 wherein themicrocontroller commands the valve to change from directing exhaustthrough the upwardly directed exhaust pipe to directing exhaust throughthe downwardly directed exhaust pipe if the ground speed sensorindicates a second speed for at least a second time.
 8. Thebi-directional tractor exhaust system of claim 6 wherein themicrocontroller commands the valve to direct exhaust through thedownwardly directed exhaust pipe when regeneration is not required.
 9. Abi-directional tractor exhaust system, comprising: a downwardly directedexhaust pipe, an upwardly directed exhaust pipe, and an intermediateexhaust pipe between the downwardly directed and upwardly directedexhaust pipes; the intermediate exhaust pipe connected to the outlet ofa diesel particulate filter; and an exhaust pipe valve in the downwardlydirected exhaust pipe that may be opened or closed by an actuator todirect exhaust through the downwardly directed exhaust pipe duringregeneration of the diesel particulate filter if a signal from a groundspeed sensor indicates ground speed above a first speed, or through theupwardly directed exhaust pipe if the ground speed is below a secondspeed.
 10. The bi-directional tractor exhaust system of claim 9 furthercomprising a microcontroller connected to the exhaust pipe valve, thediesel particulate filter and the ground speed sensor.